Poly(ester-amide) hot melt adhesives containing spheroidal metal powders

ABSTRACT

Poly(ester-amide) adhesive compositions comprising a finely divided spheroidal metal. The poly(ester-amide) comprises crystalline polyester and amorphous polyamide segments formed by reaction of a C 18  to C 54  polycarboxylic acid mixture and a C 2  to C 10  aliphatic or alicyclic primary diamine. The finely divided spheroidal metal is selected from the group consisting of aluminum, iron, mild steel, stainless steel and zinc. The weight ratio of poly(ester-amide) to metal is in the range of 70:30 to 30:70. The adhesive compositions are useful as hot melt adhesives and cavity fillings.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a poly(ester-amide) hot melt adhesivecomposition, to a method of filling voids with the adhesive compositionand to articles filled or coated with the hot melt adhesive composition.More particularly, it refers to a block copoly(ester-amide) filled witha finely divided metal powder, to a method of filling voids with such acomposition and to articles, filled or coated with the composition.

2. Description of the Prior Art

Hot melt adhesives are well known in the prior art. These materials areconveniently applied to a substrate in the molten state and upon coolingform an adhesive bond. However, a deficiency common to most of the hotmelt adhesives of the prior art is their tendency to soften and flow atelevated temperatures, as, for example, 70° to 100° C. with a resultingloss of bond strength. Consequently, these materials are not suitablefor use over a broad temperature range.

Attempts to upgrade the softening and flow temperatures have involvedusing very high molecular weight resinous materials and/or crosslinkingof the resin. These methods have resulted in materials with highersoftening points and flow temperatures. However, in most cases theresulting material was not adapted to thermal processing because of itshigher molecular weight and/or crosslinked structure resulting inextremely high application viscosity. Thus, these materials were notsuitable for use as hot melt adhesives.

A definite need exists in the art for a hot melt adhesive which isresistant to flow at temperatures around 150° C. but which can bereadily processed and applied using hot melt adhesive applicationtechniques and apparatus.

U.S. Pat. No. 3,650,999 discloses a poly(ester-amide) resin havingimproved adhesion and high temperature performance obtained by reactinga crystalline polyester, a C₁₈ to C₅₄ polycarboxylic acid and a primarydiamine. However, this poly(ester-amide) in common with other hot meltadhesives has deficiencies in creep resistance at temperatures above150° C. in the range up to 205° C. and above and in shrinkage when thehot melt is cooled to room temperature after application.

A definite need therefore exists in the art for a hot melt adhesivewhich has improved creep resistance and shrink resistance without lossin processability and ease of application.

In the manufacture and repair of metal bodies such as automobiles andappliances, solder compositions containing lead are frequently used tofill cavities and voids. These lead solders are a health hazard whichmandates special handling to protect workers and are also extremelydense. Conventional hot melt adhesives are not satisfactory for suchcavity and void filling applications because they cannot be sandedrapidly at assembly line speed, they do not readily accept paint becausethey bleed through, and they do not withstand the curing temperaturesfor the paint. Curable adhesives such as epoxies are generallyunsatisfactory because they require careful metering of the componentsto provide good physical properties and bond strength, and because theytake too long to cure to a sandable state.

A need therefore exists for a cavity or void forming composition whichis less dense and toxic than lead solder, forms a strong bond to metalsubstrate, withstands extremes of humidity and temperature, is readilyapplied and rapidly sets to a sandable state, is easily sanded smooth,and accepts paint without bleeding through.

SUMMARY OF THE INVENTION

The needs are met by the adhesive compositions of the present inventionwherein a poly(ester-amide) having crystalline polyester segments andamorphous polyamide segments is filled with a finely divided spheroidalmetal powder.

The adhesive composition comprises

a. from about 70 to about 30 parts by weight of a poly(ester-amide)block copolymer melting in the range of about 155° to about 225° C.,having from about 30 to about 70 percent by weight of crystallinepolyester segments derived from at least one aliphatic or alicyclic diolhaving from 2 to 10 carbon atoms and at least one alicyclic or aromaticdicarboxylic acid having from 8 to 20 carbon atoms, and from about 70 toabout 30 percent by weight of amorphous polyamide segments derived froman aliphatic polycarboxylic acid containing at least 40 weight percentof a C₁₈ to C₅₄ polycarboxylic acid and an aliphatic or alicyclicprimary diamine containing 2 to 10 carbon atoms; and

b. from about 30 to about 70 parts by weight of finely dividedspheroidal metal powder selected from the group consisting of aluminum,iron, mild steel, stainless steel and zinc.

Another aspect of the invention is directed to substrates coated withthe adhesive composition and yet another aspect is directed to a methodof filling a cavity in a substrate which comprises applying the adhesivecomposition as a hot melt to fill the cavity, cooling the adhesivecomposition below its crystallization temperature and sanding theadhesive composition to provide a surface even with the surroundingsubstrate.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The poly(ester-amide) component of the present invention is prepared byreacting a crystalline polyester with an amorphous polyamide or with thecomponent polycarboxylic acid and diamine by the one step or two stepmethod set forth in U.S. Pat. No. 3,650,999 which patent is incorporatedherein by reference.

The polyester reactant is considered to be a prepolymer in view of thefact that it copolymerizes with the other reactants to form a blockcopolymer. The polyester must be capable of contributing a crystallinestructure to the resulting poly(ester-amide) as is evidenced by acrystalline melting point as determined by differential thermal analysis(DTA) and/or differential scanning calorimetry (DSC) methods. Moreover,the polyester should have a melting point higher than 180° C. andpreferably in the range of from 200° to 270° C. and an inherentviscosity in the range of from 0.05 to 0.70 when measured as a 0.5 gramsolution of polyester in 100 ml. of a 60/40 phenol/tetrachloroethanesolvent pair at 25° C.

The present invention uses a polyester reactant that contributescrystalline blocks to the resulting poly(ester-amide) hot melt adhesivecomposition. Consequently, optimum bulk stage physical properties suchas tensile and high modulus are achieved without occurring thedisadvantage of a high processing viscosity.

An inherent viscosity of from 0.05 to 0.70 is required for the polyesterin order to insure that the polyester will contribute the optimumcrystalline structure to the final polymeric product. Polyesters with anintrinsic viscosity below 0.05 have a short chain length and cannotcontribute the necessary crystalline structure to the final polymericproduct which also comprises amorphous polyamide blocks. Inherentviscosities greater than about 0.70 require excessive reaction times ortemperatures to form homogenous poly(ester-amides). Thus, it isimpractical to use polyester reactants with intrinsic viscositiesgreater than 0.70 in the practice of the present invention. Moreover,excessive reaction times and temperatures tend to cause degradation ofthe polymer and a subsequent loss in adhesive properties.

The minimum melting point requirement of about 180° C. for the polyesterreactant is necessary in order to insure that the final polymericproduct has excellent thermal properties such as resistance to flow atelevated temperatures. Preferably, the melting point of the polyester isin the range of from 200° C. to 270° C.

Representative examples of high melting crystalline polyesters suitablefor use in the present invention include polymeric ethyleneterephthalate, neopentyl terephthalate, ethylene 2,6-naphthalate,tetramethylene terephthalate, tetramethylene 2,6-naphthalate,trimethylene 2,6-naphthalate, 1,4-cyclohexylene dimethyleneterephthalate, and copolyesters, such as copolyesters of ethyleneterephthalate containing at least 50 mol percent of ethyleneterephthalate, such as 95/5, 90/10, 85/15 and 50/50 ethyleneterephthalate-ethylene isophthalate copolyesters, ethyleneterephthalate-ethylene adipate copolyesters, and ethyleneterephthalate-ethylene hexahydroterephthalate copolyesters,tetramethylene terephthalate-tetramethylene azelate copolyesterscontaining at least 80 mol percent of tetramethylene terephthalate,1,4-cyclohexylene dimethylene terephthalate-azelate copolyesterscontaining 70 to 90 mol percent of 1,4-cyclohexylene dimethyleneterephthalate, copolyesters of ethylene 2,5- and 2,6-naphthalatecontaining from 80 to 90 mol percent of the ethylene naphthalate, suchas ethylene 2,5-naphthalate-ethylene azelate and ethylene2,6-naphthalate-ethylene azelate copolyesters. These polyester blockscan be derived from various dicarboxylic acids and various glycols.Representative examples of such acids are terephthalic acid, isophthalicacid, hexahydroterephthalic acid, the naphthalic acids, such as 2,6-,2,7-, 2,8-, 1,5- and 1,4-naphthalene dicarboxylic acids and other suchacids which form high melting polyester resins. Examples of glycols areethylene glycol, propylene glycol, tetramethylene glycol, neopentylglycol, 1,4-cyclohexane diol, 1,4-cyclohexane dimethanol and other suchglycols. High melting polymers containing components such as2,2-dimethyl propane diol, form polyesters which have melting pointsabout 234° C. Mixtures of the foregoing polyesters can also be used.

Preferably, a polyester from the following group is used to prepare thepolyesteramide component of the present invention:

Poly(ethylene terephthalate/isophthalate), 100/0 to 75/25;

Poly(ethyelne/hexamethylene terephthalate), 100/0 to 75/25;

Poly(ethylene/neopentyl terephthalate), 100/0 to 75/25;

Poly(tetramethylene terephthalate/isophthalate), 100/0 to 75/25;

Poly(tetramethylene/hexamethylene terephthalate), 100/0 to 75/25;

Poly(tetramethylene/neopentyl terephthalate), 100/0 to 75/25;

Poly(ethylene/propylene terephthalate), 100/0 to 60/40; and

Poly(tetramethylene - 2,6 - naphthalate/terephthalate), 100/0 to 75/25;etc.

The amide portion of the polyester-amide adhesive components of thisinvention are amorphous block segments which contribute wettability,elasticity and rubber character to the adhesive composition. Thepolyamide portion of the polyester-amide composition of the presentinvention is the reaction product of a C₁₈ to C₅₄ polycarboxylic acidand an aliphatic primary diamine. The polycarboxylic acids are wellknown in the art and are described in detail in U.S. Pat. No. 3,157,681and other references. These materials are available commercially asmixtures of monobasic, dibasic and tribasic acid with the dibasic acidbeing present as the major component of the mixtures. These materialsgenerally have a composition as follows:

    ______________________________________                                                           Percent by Weight                                          ______________________________________                                        C.sub.18 monobasic acids                                                                           0 - 10                                                    (Monoacids)                                                                  C.sub.36 dibasic acids                                                                             80 - 100                                                  (Dimer acids)                                                                C.sub.54 and higher polybasic acids                                                                0 - 10                                                    (Trimer acids)                                                               ______________________________________                                    

The relative ratios of monomer, dimer and trimer in such unfractionatedpolymeric fat acids are dependent on the nature of the startingmaterials and the conditions of polymerization. For the purposes of thisinvention, the term polycarboxylic also includes mixtures of the mono,di and tribasic acids.

The aliphatic or alicyclic primary diamines used in this inventioncontain from 2 to 10 carbon atoms. These include ethylene diamine,1,3-propane diamine, 1,4-butanediamine, 1,5-pentane diamine,hexamethylene diamine, 1,10-decanediamine, cyclohexyldiamine,2,2-dimethyl-1,3-propane diamine, etc.

Optionally up to 60 percent by weight of a linear aliphatic dibasic acidhaving from 4 to 10 carbon atoms may be substituted for a correspondingamount of the C₁₈ to C₅₄ polycarboxylic acid used to prepare thisportion of the polyesteramide. Examples of these acids would includeoxalic, malonic, succinic, glutaric, adipic, pimelic, suberic, azelaic,and sebacic acids. The advantage of substituting the C₄ to C₁₀ acids forthe C₁₈ to C₅₄ acids is to permit more heterogeneous character to thepolyamide portion of the polymer in those applications where a moreheterogeneous character is desired.

The poly(ester-amide) component of the present invention contains 30 to70 percent by weight of polyamide segment and correspondingly, from 30to 70 percent by weight of crystalline polyester segments. Preferably,it contains 40 to 60 percent by weight of polyamide segment andcorrespondingly, from 60 to 40 percent of crystalline polyestersegments. The poly(ester-amides) are further characterized as having aninherent viscosity in the range of from 0.35 to 0.95 and more preferablyfrom 0.40 to 0.6 when measured as a 0.5 gram solution ofpoly(ester-amide) in 100 ml. of a 60/40 phenol/tetrachloroethane solventpair at 25° C. The crystalline melting point of these materials asmeasured by DTA or DSC is in the range of from 155° to 225° C. and themelt viscosity at 220° C. is in the range of from 5000 to 65,000centipoises. The poly(ester-amide) resins are soluble in a 60/40phenol/tetrachloroethane solvent pair and insoluble in a 1/1toluene/isopropanol solvent pair. Moreover, the 1/1 toluene/isopropanolextractable content of the poly(ester-amide) resins is less than 2percent. In view of the fact that the polyamide portion is soluble intoluene/isopropanol solvent pair the very low order of extractables forthe poly(ester-amide) resins demonstrates that they are true blockcopolymers and not physical blends of polyester and polyamide segments.

The poly(ester-amide) is prepared by a one step or two step method. Inthe one step method the acid and amine components, which go to form thepolyamide segment are polymerized in the presence of the crystallinepolyester prepolymer. In the two step method the polyamide and polyesterprepolymer segments are prepared separately and then reacted together toform the polyester-amide. These methods are discussed in greater detailin the working examples of U.S. Pat. No. 3,650,999.

The morphological properties of the poly(ester-amides) are determined ona duPont differential thermal analyzer Model DTA 900 using thedifferential scanning calorimeter attachment, with a 5 to 25 mg sampleheated at a rate of 20° C. in a nitrogen atmosphere. The glasstransition point (T_(g)) is the onset of the increase in specific heatof the polymer and is the intersection of the base line and the slope ofincreasing specific heat; the melting point (T_(m)) is the temperatureobserved at the apex of the melting endotherm peak.

The second component of the adhesive composition is a finely dividedspheroidal metal powder selected from the group consisting of aluminum,iron, mild steel, stainless steel and zinc. The metal powder issubstantially uniformly dispersed in the poly(ester-amide). It may be ofnumber average particle size in the range of 0.2 micron to 150 micronand is preferably of number average particle size in the range of 4 to100 micron. The preferred metal filler is atomized aluminum particularlywhen the adhesive composition is used for cavity filling since it allowsthe hot melt composition to be readily smoothed and burnished when it issanded. In general, plate-like, acicular, or multi-faceted granularpowdered metals are unsatisfactory, surprisingly causing high viscosityin the hot melt and "blinding" or filling and occlusion of sand paperwhen the filled composition is sanded.

The amount of metal powder which is dispersed in the poly(ester-amide)is sufficient to improve the high temperature creep resistance withoutcausing unmanageable rheology. It is preferably in the range of about 30to about 70 parts by weight of metal powder dispersed in about 70 toabout 30 parts by weight of poly(ester-amide). The melt viscosity of thehot melt composition containing the metal filler is preferably less thanabout 150,000 centipoises at a temperature of 232° C. and a shear rateof 3-4 sec.⁻¹ measured in a Brookfield Thermocel Unit Model HBT. Above150,000 centipoise melt viscosity, the hot melt is difficult to applyand spread, and tends to be dragged from the point of application.

Creep resistance of the filled poly(ester-amide) compositions of thepresent invention is determined by observing the sag of a 10 to 15 gramsample of the composition placed on an aluminum plane inclined at 60° tothe vertical. The observations are carried out at 175° and 205° C. Creepor sag in less than 60 minutes at the designated temperature is recordedas a failure to meet the test.

Lap bond tensile strength is determined by ASTM Test Method D-1002-72. Aminimum of 100 kg per sq. cm. is preferred.

Sandability of the filled compositions is determined by applying thecomposition as a hot melt to a smooth steel panel 7.5 × 22.5 cm. toprovide a strip 4 cm. wide and in the range of 25 to 250 microns thick.The panel is cooled to room temperature and a disc sander, 12.5 cm.diameter, with 80 grit medium tungsten carbide abrasive, is applied tothe composition at 1000 rpm to smooth and feather the composition. Ifthe surface of the composition becomes smooth enough to accept paintwithout "telegraphing" or showing a difference in reflectivity betweenthe painted steel and the painted composition, and without blinding orblocking the abrasive surface of the sander, the composition is ratedsandable.

When the hot melt composition is formed by mixing the filler with themelted polymer, a good mix is considered to have been obtained if thefiller particles are evenly distributed throughout the melt. In poormixes, the filler particles are not adequately wet by the melt, and arenot evenly distributed remaining aggregated within the melt. Meltstability of the mix is determined by maintaining the mix at 216° C. for2 hours. If the melt viscosity changes less than ±10 percent during thistime, the mix is considered to have melt stability.

In addition to improving the creep resistance of the poly(ester-amide)component, the metallic component improves the rate of melting of theadhesive composition, allows the composition to be applied and spreadmore easily with less pressure, imparts longer "open" time betweenapplication of the hot melt and closing of the bond and higher "green"strength or faster onset of bond strength, and reduces the degree ofshrinkage of the adhesive composition when it is cooled from the hotmelt temperature to ambient temperature. The cost of the composition isalso considerably reduced. When the composition is used to fillcavities, it can be readily sanded as discussed above, withstandsextremes of temperature and humidity, is exceptionally solvent resistantand is readily painted without abosrbing solvent, swelling, andblistering.

The hot melt adhesive compositions of the present invention findwidespread utility wherever hot melt adhesives are used. They areespecially valuable in those applications where resistance to creep atelevated temperatures is a necessary requirement. The adhesivecompositions of the present invention may be used to great advantage tobond a variety of substrates including metal, glass, synthetic andnatural textiles, leathers, synthetic polymeric sheet material, wood,paper, etc.

The present invention also includes the concept of incorporating variousingredients into the poly(ester-amide) resins of the present inventionin order to improve processing and/or performance of these materials.These additives and adjuncts include antioxidants, thermal stabilizers,extenders, dyes, pigments, adhesion promoters, plasticizers, etc.

The following examples are set forth in illustration of this inventionand should not be construed as a limitation thereof. Unless otherwiseindicated, all parts and percentages are by weight.

EXAMPLE I

A block copolymer which is approximately 60 percent by weightcrystalline polyethylene terephthalate segments and 40 percent by weightamorphous polyamide made from dimer acid and hexamethylene diamine isprepared in two steps. In the first step 157.5 parts (0.272 mol) of aC₃₆ dibasic acid and 30.8 parts (0.266 mol) of 1,6-hexane diamine arecharged to a reaction vessel and heated with agitation at about 215° C.for 1 hour to form a polyamide resin. During the first 30 minutes thepressure rises to 264 g/cm² after which time the reaction vessel isvented to reduce the pressure to 158 g/cm² . At the end of 1 hour thepressure is released and 269 parts of a crystalline polyethyleneterephthalate (M.P.=260° C./inherent viscosity 0.147) and 5.9 parts(0.095 mol) of ethylene glycol are charged to the vessel along with aminor amount of an antioxidant. The vessel is flushed with nitrogen andthe mixture is heated to about 280° C. while maintaining a nitrogenpressure of 70 g/cm² After 0.5 hour the vessel is vented and vacuumapplied and the reaction is continued under full vacuum (0.1 to 5 mm. ofmercury) for 2 hours. At the end of this time the resulting moltenpoly(ester-amide) is discharged under pressure into a water bath toquench the material. The polymer obtained melts at 185° C. and theinherent viscosity is 0.50. To a stainless steel reactor fitted with ananchor agitator and a jacketed hot oil heating system is added 100 partsby weight of the poly(ester-amide) and heating is begun. When thecontents have reached 250° C., agitation is begun at 60 rpm and 100parts by weight dry aluminum powder (Alcoa Atomized Powder 123) is fedinto the mass at a rate of 10 parts by weight per minute. The agitationis continued and the temperature raised to 266° C. under a nitrogenblanket. Agitation is continued for 15 minutes after the second additionis completed and the molten mass is discharged under slight N₂ pressure(70 g/cm²) quenched in a bath, ground and redried. This material is usedto as a hot melt to fill dents and orifices in large metal structures.After application it is cooled to room temperature, sanded smooth with80 grit tungsten carbide abrasive and painted with an automotivetopcoat. No "telegraphing" is observed.

EXAMPLE 2

Into a sigma-bladed mixer heated by a hot oil external jacket is placed5.0 parts by weight poly(ester-amide) of Example 1. Heat is applied andat 216° C. agitation is begun. When the mass is molten, 5.0 parts byweight of aluminum powder of average particle size 15 to 19 microns,sold by the Aluminum Company of America under the tradename AlcoaAtomized Powder No. 123) is fed over a period of 10 minutes. Afteraddition is completed, heating and agitation is continued for 15minutes. At this point heating is stopped and under agitation cooling isbegun. With agitation under cooling the molten mass becomes friable andbreaks up into free flowing aggregate mixture ranging in size from 1/16to 1/2 inch. This material is suitable for application as an adhesive orbody filling compound when remelted.

EXAMPLE 3

A preblended mixture of 100 parts of the block copoly(ester-amide) ofExample 1 and 100 parts of aluminum powder (Alcoa Powder No. 123) is fedfrom a hopper continuously into a Farrel Continuous Mixer whosetemperature controls are set at 216° C. The mass is continouslydischarged (estimated hold up time 8-10 minutes) on a cooled conveyerbelt and ground. Alternately the extruded ribbon is conveyed into acooling bath, air blown, dried and ground in conventional grindingequipment. The free flowing aggregate is suitable for use as an adhesiveand/or void filling compound when remelted and applied.

EXAMPLES 4-6

These examples show the effect of varying the filler content of thepoly(ester-amide) adhesive composition. The poly(ester-amide) of Example1 is blended in the manner set forth in Example 1, with 50, 150 and 200parts of Alcoa Atomized Powder No. 123 per 100 parts ofpoly(ester-amide) respectively. The data are presented in Table 1.

                  TABLE 1                                                         ______________________________________                                        Block Copoly(ester-amide) Filled with Atomized Aluminum                       Filler                                                                        Parts per  Melt                                                               100 parts  Viscosity                                                                              Melt    Creep                                             Poly(ester-                                                                              10.sup.-5 cps,                                                                         Stabi-  Resistance                                                                              Sand-                                   Ex.  amide)    4 sec.sup.-1                                                                           lity  175° C                                                                       205° C                                                                       ability                             ______________________________________                                        1    100       35       Stable                                                                              Pass  Pass  Pass                                4     50       28       Stable                                                                              Pass  Pass  Marginal                            5    150       56       Stable                                                                              Pass  Pass  Pass                                6    200       >100     Stable                                                                              Pass  Pass  Pass                                0     0        20       Stable                                                                              Fail  Fail  Fail                                ______________________________________                                    

EXAMPLES 7-8

In these examples, copoly(ester-amide) filled with flake aluminum isprepared and compared with copoly(ester-amide) filled with atomizedaluminum. The poly(ester-amide) of Example 1 is blended with filler inthe manner set forth in Example 1. The data are presented in Table 2.The flake aluminums of Examples 7 and 8 are produced by Reynolds andsold under the tradenames IF75 Flake Aluminum 40XD and 3XD respectivelyand have average particle sizes less than 44 microns. Extremely highmelt viscosity is obtained even at low concentrations of filler.

                                      TABLE 2                                     __________________________________________________________________________    Comparison of Block Copoly(ester-amide) Filled with Atomized and Flake        Aluminum                                                                                 Filler:                                                                              Melt                                                                   Poly(ester-                                                                          Viscosity                                                              amide) 10.sup.-3 cps,                                                                     Melt Creep Resistance                                  Example                                                                            Filler                                                                              Weight Ratio                                                                         4 sec.sup.-1                                                                       Stability                                                                          175° C.                                                                     205° C.                                                                    Sandability                              __________________________________________________________________________    1    Atomized                                                                            1:1    35   Stable                                                                             Pass Pass                                                                              Pass                                          Aluminum                                                                            1:2    28   Stable                                                                             Pass Pass                                                                              Pass                                     4    Atomized                                                                      Aluminum                                                                 7    Flake 1:2    >300 Stable                                                                             Pass Pass                                                                              Blinds                                        Aluminum                                                                 8    Flake 1:4    >300 Stable                                                                             Pass Pass                                                                              Blinds                                        Aluminum                                                                 __________________________________________________________________________

EXAMPLES 9-16

These examples set forth a comparison between copoly(ester-amide) filledwith inorganic mineral pigments and with atomized aluminum. Thepoly(ester-amide) of Example 1 is blended with filler in the manner setforth in Example 1. The data are presented in Table 3. In general theinorganic fillers tend to be incompatible, to give high viscosity, poormix stability and poor sandability. Barium sulfate demonstrates afurther disadvantage, namely instability at the hot melt mixingtemperature and evolution of acrid fumes of sulfur trioxide. Theoleophilic clay of Examples 9 and 10 is supplied by Georgia KaolinCompany under the Tradename Kaogan 45.

                                      TABLE 3                                     __________________________________________________________________________    COMPARISON OF INORGANIC MINERAL PIGMENTS WITH ATOMIZED ALUMINUM                          Filler:                                                                              Melt                                                                   Poly(ester-                                                                          Viscosity                                                              amide) 10.sup.-3 cps,                                                                       Melt  Creep Resistance                               Example                                                                            Filler                                                                              Weight Ratio                                                                         4 sec.sup.-1                                                                         Stability                                                                           175° C.                                                                     205° C.                                                                    Sandability                           __________________________________________________________________________     1   atomized                                                                            1:1    35     Stable                                                                              Pass Pass                                                                              Pass                                       aluminum                                                                  4   atomized                                                                            1:2    28     Stable                                                                              Pass Pass                                                                              Pass                                       aluminum                                                                  9   oleophilic                                                                          1:1    >300   Poor  Pass --  Blinds                                     clay                                                                     10   oleophilic                                                                          1:2    100    Poor  Pass --  Blinds                                     clay                                                                     11   calcium                                                                             1:1    Incompatible                                                                         Poor  Pass --  --                                         carbonate           mix                                                  12   calcium                                                                             1:2    Incompatible                                                                         Poor  --   --  --                                         carbonate    mix                                                         13   titanium                                                                            1:1    >300   Poor  --   --  --                                         dioxide             mix                                                  14   titanium                                                                            1:2    25     --    Fail Fail                                                                              Pass                                       dioxide                                                                  15   barium                                                                              1:1    55     Very poor                                                                           Pass Pass                                                                              Pass                                       sulfate             acrid fumes                                          16   barium                                                                              1:2    40     Very poor                                                                           Pass Fail                                                                              Pass                                       sulfate             acrid fumes                                          __________________________________________________________________________

EXAMPLES 17-25

These examples are prepared by filling commercially available polyesterand polyamide hot melt adhesives with atomized aluminum powder (AlcoaAtomized Powder No. 123) in the manner set forth in Example 1. The dataare presented in Table 4. The weight ratio of polymer to filler is 1:1.The data show that compositions containing commercial polyesters andpolyamides generally fail the creep test and the sandability test andthat those which marginally pass the sandability test and the creep testare of such high viscosity that they are difficult to apply.

                                      TABLE 4                                     __________________________________________________________________________    Comparison Of Filled Block Copoly(Ester-Amide) With Filled Polyesters And     Polyamides                                                                                     MELT                                                                          VISCOSITY                  LAP BOND                                           10.sup.-3 cps,                                                                       CREEP RESISTANCE    TENSILE STRENGTH                  EXAMPLE                                                                              POLYMER   4 sec.sup.-1                                                                         175° C.                                                                      205° C.                                                                     SANDABILITY                                                                            kg/cm.sup.2                       __________________________________________________________________________     1     block     35.0   pass  pass pass     197                                      copoly(ester-amide)                                                    17     Polyester A                                                                             35.5   fail  fail blinds   211                               18     Polyester B                                                                             132.4  pass  fail pass     106                               19     Polyester C                                                                             17.5   fail  fail blinds   134                               20     Polyester D                                                                             >500   pass  fail marginal 106                               21     Polyamide A                                                                             22     fail  fail blinds    78                               22     Polyamide B                                                                             28     fail  fail blinds   120                               23     Polyamide C                                                                             6.0    fail  fail blinds   134                               24     Polyamide D                                                                             135.0  fail  fail blinds    78                               25     Polyamide E                                                                             >300   pass  pass marginal 183                               __________________________________________________________________________

What is claimed is:
 1. An adhesive composition comprising:a. from about60 to about 30 parts by weight of a poly-(ester-amide) block copolymermelting in the range of about 155° to about 225° C. having from about 30to about 70 percent by weight of crystalline polyester segments derivedfrom at least one aliphatic or alicyclic diol having from 2 to 10 carbonatoms and at least one alicyclic or aromatic dicarboxylic acid havingfrom 8 to 20 carbon atoms, and from about 70 to about 30 percent byweight of amorphous polyamide segments derived from an aliphaticpolycarboxylic acid containing at least 40 weight percent of a C₁₈ toC₅₄ polycarboxylic acid and an aliphatic or alicyclic primary diaminecontaining 2 to 10 carbon atoms; and b. from about 40 to about 60 partsby weight of finely divided spheroidal metal powder selected from thegroup consisting of aluminum, iron, mild steel, stainless steel and zincof particle size in the range of about 0.2 to about 150 microns.
 2. Theadhesive composition of claim 1 wherein the polyester is selected fromthe group consisting of poly(ethylene-terephthalate), co-poly(butyleneterephthalate)-(ethylene terephthalate),co-poly(ethylene-terephthalate)-(ethyleneisophthalate) andcopoly(ethylene terephthalate)-(propylene terephthalate).
 3. Theadhesive composition of claim 1 wherein the diamine is hexamethylenediamine.
 4. The adhesive composition of claim 1 having a melt viscosityat 232° C. of less than about 150,000 centipoise at a shear rate of 4sec.⁻¹.
 5. The adhesive composition of claim 1 wherein the polyestersegment prior to incorporation in the polyesteramide has an inherentviscosity at 25° C. in the range of about 0.05 to about 0.70 measured asa 0.5 gram solution in 100 ml. of a solvent mixture of 60 parts byweight of phenol and 40 parts by weight of symm-tetrachloroethane and amelting point in the range of about 180° to about 270° C.
 6. Theadhesive composition of claim 1 wherein the poly(ester-amide) has aninherent viscosity at 25° C. in the range of from 0.35 to about 0.95measured as a 0.5 gram solution in 100 ml. of a solvent mixture of 60parts by weight of phenol and 40 parts by weight ofsymm-tetrachloroethane.
 7. The adhesive composition of claim 1 whereinthe spheroidal metal powder has a particle size in the range of about 4to about 100 microns.
 8. An adhesive composition comprising:a. fromabout 70 to about 30 parts by weight of a poly (ester-amide) blockcopolymer of inherent viscosity in the range of about 0.35 to about 0.95and of melting point in the range of about 155° to about 225° C., havingfrom about 30 to about 70 percent by weight of crystalline polyestersegments selected from the group consisting ofpoly(ethylene-terephthalate), co-poly (butylene terephthalate)-(ethyleneterephthalate), co-poly(ethylene-terephthalate)-(ethylene isophthalate)and co-poly(ethylene terephthalate)-(propylene terephthalate) whichprior to incorporation in the poly(ester-amide), have an inherentviscosity in the range of about 0.05 to about 0.70 and a melting pointin the range of about 180° to about 270° C., and from about 70 to about30 percent by weight of amorphous polyamide segments derived from a C₃₆dibasic acid and an aliphatic or alicyclic diamine containing from 2 to10 carbon atoms, the inherent viscosities being determined at 25° C.with an 0.5 gram solution in 100 ml. of a solvent mixture of 60 parts byweight of phenol and 40 parts by weight of symm-tetrachloroethane; andb. from about 30 to about 70 parts by weight of spheroidal aluminumpowder of particle size in the range of about 4 to about 100 microns. 9.The adhesive composition of claim 8 wherein the diamine is hexamethylenediamine.
 10. The adhesive composition of claim 8 having a melt viscosityat 232° C. of less than about 150,000 centipoise at a shear rate of 4sec.⁻¹.
 11. A substrate coated with an adhesive composition wherein theadhesive composition comprises:a. from about 60 to about 30 parts byweight of a poly (ester-amide) block copolymer melting in the range ofabout 155° to about 225° C. having from about 30 to about 70 percent byweight of crystalline polyester segments derived from at least onealiphatic or alicyclic diol having from 2 to 10 carbon atoms and atleast one alicyclic or aromatic dicarboxylic acid having from 8 to 20carbon atoms, and from about 70 to about 30 percent by weight ofamorphous polyamide segments derived from an aliphatic polycarboxylicacid containing at least 40 weight percent of a C₁₈ to C₅₄polycarboxylic acid and an aliphatic or alicyclic primary diaminecontaining 2 to 10 carbon atoms; and b. from about 40 to about 60 partsby weight of finely divided spheroidal metal powder selected from thegroup consisting of aluminum, iron, mild steel, stainless steel and zincof particle size in the range of about 0.2 to about 150 microns.
 12. Thesubstrate of claim 11 wherein the polyester block of thepoly(ester-amide) is selected from the group consisting ofpoly(ethylene-terephthalate), co-poly(butylene terephthalate)-(ethyleneterephthalate), co-poly(ethylene-terephthalate)-(ethylene isophthalate)and co-poly(ethylene terephthalate)-(propylene terephthalate).
 13. Thesubstrate of claim 11 wherein the diamine of the amide block of thepoly(ester-amide) is hexamethylene diamine.
 14. The substrate of claim11 wherein the melt viscosity of the adhesive composition at 232° C. isless than about 150,000 centipoise at a shear rate of 4 sec.⁻¹.
 15. Thesubstrate of claim 11 wherein the polyester segment prior toincorporation in the poly(ester-amide) has an inherent viscosity at 25°C. in the range of about 0.05 to about 0.70 measured as an 0.5 gramsolution in 100 ml. of a solvent mixture of 60 parts by weight of phenoland 40 parts by weight of symm-tetrachloroethane and a melting point inthe range of about 180° to about 270° C.
 16. The substrate of claim 11wherein the poly(ester-amide) has an inherent viscosity at 25° C. in therange of from 0.35 to about 0.95 measured as an 0.5 gram solution in 100ml. of a solvent mixture of 60 parts by weight of phenol and 40 parts byweight of symm-tetrachloroethane.
 17. The substrate of claim 11 whereinthe spheroidal metal powder has a particle size in the range of about 4to about 100 microns.
 18. A substrate coated with an adhesivecomposition wherein the adhesive composition comprises:a. from about 70to about 30 parts by weight of a poly (ester-amide) block copolymer ofinherent viscosity in the range of about 0.35 to about 0.95 and ofmelting point in the range of about 155° to about 225° C., having fromabout 30 to about 70 percent by weight of crystalline polyester segmentsselected from the group consisting of poly(ethylene-terephthalate),co-poly (butylene terephthalate)-(ethylene terephthalate,co-poly(ethylene-terephthalate)-(ethylene isophthalate) andco-poly(ethylene terephthalate)-(propylene terephthalate) which prior toincorporation in the poly(ester-amide), have an inherent viscosity inthe range of about 0.05 to about 0.70 and a melting point in the rangeof about 180° to about 270° C., and from about 70 to about 30 percent byweight of amorphous polyamide segments derived from a C₃₆ dibasic acidand an aliphatic or alicyclic diamine containing from 2 to 10 carbonatoms, the inherent viscosities being determined at 25° C. with an 0.5gram solution in 100 ml. of a solvent mixture of 60 parts by weight ofphenol and 40 parts by weight of symm-tetrachloroethane; and b. fromabout 30 to about 70 parts by weight of spheroidal aluminum powder ofparticle size in the range of about 4 to about 100 microns.
 19. Thesubstrate of claim 18 wherein the diamine of the amide block of thepoly(ester-amide) is hexamethylene diamine.
 20. The substrate of claim18 wherein the melt viscosity of the adhesive composition at 232° C. isless than about 150,000 centipoise at a shear rate of 4 sec.⁻¹.